The Angels announced Moran's diagnosis on Tuesday. The club was hopeful he could be a key lefty in coming out of the bullpen after the Angels selected Moran in December's winter meeting draft from Toronto.
Moran began to feel problems with his elbow during spring training, but the need for surgery was only determined in the last few days, Angels manager Mike Scioscia said Tuesday.
Moran, 25, has never pitched in the major leagues. He spent last season in Seattle's minor league system pitching at Triple-A Tacoma, where he had a 3.45 ERA in 48 appearances.